[1]
K. S. Khalina, “Boundary controllability problems for the equation of oscillation of an inhomogeneous string on a semiaxis”,
Ukr. Mat. Zhurn., vol. 64, no. 4, pp. 525–541, Apr. 2012, Accessed: Apr. 13, 2025. [Online]. Available:
https://umj.imath.kiev.ua/index.php/umj/article/view/2593